In MRI imaging, a pre-pulse may be applied to selectively excite a proton signal of a specific region, thereby improving the image quality or imaging the additional information. When selectively exciting only a proton signal of a specific region, an RF pulse for two-dimensional selective excitation and a gradient magnetic field for two-dimensional selective excitation are applied in combination. Examples of such an RF pulse for two-dimensional selective excitation (two-dimensional selective excitation pulse) include a labeling IR (Inversion Recovery) pulse in ASL (Arterial Spin Labeling) which gives a magnetic mark (label) to the blood flow.
Since the IR pulse is often applied to the fluid outside the imaging plane, the timing at which the fluid flows into the imaging plane after IR pulse is applied has a large influence on image quality. When the IR pulse is used as a two-dimensional selective excitation pulse, the labeling range is narrower than that in the normal case. For this reason, the case where the IR pulse is used as a two-dimensional selective excitation pulse is more sensitive to timing.
As a specific example of application, there is non-contrast perfusion (refer to NPL 1) or renal artery imaging (refer to NPL 2).